Power management in a data processing system often involves techniques for reducing the consumption of power by components or subsystems in the data processing system. The data processing system may be a laptop or otherwise portable computer, such as a handheld general purpose computer or a cellular telephone. The management of power consumption in a portable device which is powered by a battery is particularly important because better power management usually results in the ability to use the portable device for a longer period of time when it is powered by one or more batteries.
A data processing system and its components and subsystems may have configurable system settings which allow a user to adjust certain performance characteristics. The manner in which these system settings are configured may affect the amount of power used by the system and/or components. While the effect on power usage of certain system settings may be intuitive to a user; for other system settings, the effect may be unknown. In particular, there is no easy way of determining how the configuration of these system settings will affect power usage and, consequently, the remaining battery life for the data processing system.
One example of a component in a data processing system is a display or monitor. The display may be, for example, a liquid crystal display (LCD) panel. Generally, an LCD panel functions by applying a current to a semiconductor substrate. Depending on the manufacturing process used, the application of the current either lets light pass through the substrate (displaying a light area on the screen) or prevents light from passing (displaying a dark area on the screen). Thus, for some displays, it may require more power to keep the display generally dark, while for others, more power is required to keep the display generally light. In conventional data processing systems, the user cannot tell how a configuration of display settings (e.g., a generally light or generally dark display theme) for the LCD will affect power usage.